<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
</head>
<body>

</body>
</html>

<!-- <script type="text/javascript">
	//数组的引用
	var arr1 = [10,20,30,40]
	var arr2 = arr1.concat()//concet()拷贝原数组
	arr2.push(60,70)
    document.write(arr2+"</br>")
    document.write(arr1)
</script> -->

<!-- <script type="text/javascript">

	alert(num)//显示undefined数据类型

</script> -->

<!-- <script type="text/javascript">
	var num=0
	function show() {
		var num = 20;
		
	}
	show()
	alert(num)  
</script> -->

<!-- <script type="text/javascript">
	var arr1=[10,20,30]
	var arr2=['hello',true,0,arr1]
	alert(arr2[3][2])
</script> -->

<!-- <script type="text/javascript">
	var arr = [[1,2,3,4,5],[6,7,8,9,10],[11,12,13,14,15],[16,17,18,19,20],[21,22,23,24,25]]
	// alert(arr[4][3])//二维数组是人为的

    var arr1=new Array(25)
    var arr = []
	for (var i = 0;i < 25; i++) {
		arr1[i]=i+1
	}
	

	for (var i = 0; i < 5; i++) {
		var newarr = arr1.splice(0,5);
		arr.push(newarr)
	}
	alert(arr[4][3])

	for (var i = 0; i < 5; i++) {
		for (var j = 0; j <= i; j++) {
			document.write[arr[i][j]+" "]
		}
		document.write["<br/>"]
	}
</script> -->

<script type="text/javascript">
	var arr = [9,8,7,6,5,4]
	for (var i = 0; i < arr.length-1; i++) {
		for (var j = 0; j < arr.length-i; j++) {
			if(arr[j]>arr[j+1]){
				var temp = arr[j]
				arr[j]=arr[j+1]
				arr[j+1]=temp
			}
		}
	}
	alert(arr)
</script>